Speaker Placement
Placement for Varying
Listening Positions
If you want the freedom to sit anywhere in a room facing any direction, and/or find that you prefer the “all around you” sound of some car stereos to a conventional “sound stage” facing you, consider the speaker placement techniques profession- al installers use in restaurants and bars. They place speakers in an array around the listening area, so that the music is always surrounding you, regardless of the direction you face.
The rule of thumb is to add one pair of speakers for every 100 to 200 square feet of listening area. Curiously, this is not so that you can play the music louder, but so that you can play it softer! When you have only one pair of speakers in a large room you will notice that when the sound is perfect in one part of the room, it is too loud near the speakers. By placing more than one pair in the room you will avoid these “hot spots” of loud sound and you will create more sonic ambiance while maintaining clarity and a rich sound everywhere (See Figure 5).
You can make listener position still less critical by using mono rather than stereo. This can be difficult to achieve with nor- mal stereo amplifiers. However, Niles manufactures Systems Integration Amplifiers® which enable one room to be wired in stereo while other rooms are wired in mono! Consult your local Niles dealer for more information.
In smaller rooms or rooms that are infre- quently used, you typically can’t justify the expense of more than two speakers. Try to bracket the room with the two speakers. Diagonal placement is a very effective way to stretch the coverage pat- tern of two speakers. You can also com- promise between direct sound (for detail and clarity) and reflected sound (the ambi-
ent or “all around you” effect). The speak- ers can be placed near corners to create more reflected sound. By directing the tweeters to point away from the listener, so they create as much reflected sound as possible, you emphasize the ambient effect. The more reflected sound there is in the room the stronger the ambient effect at low volumes. You should use moderation, however, otherwise the com- promise becomes too one sided and at high volumes, the sound will be blurred and less distinct.
Placement for Home Theater Rear Applications
In a home theater, the goal is to reproduce the experience of a great movie theater in our homes. The biggest difference between the two is the rear or surround speaker array in a commercial theater. Here, it is not uncommon to see twenty or thirty speakers around the audience. This huge array of speakers assures that you will feel completely surrounded by the ambient soundtrack of the movie. Film makers try to use the “surround” sound- track to envelope you in the environment on screen. They will place background music, rain sounds, traffic noise, etc. on the “surround” soundtrack. In a home with a single pair of speakers it is easy for the jungle sounds to sound like they are “in the middle of your head” just like headphones!
A single pair of CM5PR or CM6PR Loudspeakers, properly placed, can create a very convincing simulation of an array of speakers. If you place them near a hard reflecting surface you can make one pair of speakers sound like several. Create as many reflections as possible by placing the speakers near a corner so that the adjoining walls will act as a powerful reflector. Direct the tweeters so that sound is pointed away form the listener creating
Figure 17
Tightening the mounting “dogs”
9.Setting the Bass and Treble cut switch- es. Listen to a well-recorded piece of music at the user’s favorite listening position. a) Listen for bass boominess, particularly when the speaker is placed near a corner. Use the -2dB Bass cut to correct. b) Listen for treble harshness or ringing, particularly when the speakers are placed in a room without carpet/ Use the -2dB Treble cut switch to correct.
10.Install the grille into the speaker. The grilles should fit snugly. If you have diffi- culty fitting them in, try loosening the mounting dog screws (excessive tighten- ing can distort the shape of the frame holding the grille in place).
Painting the Speakers
All models may be painted. The plastic will readily accept most paints.
The speakers must be masked prior to painting them. The inside circular portion of the hole template can be used as a paint mask. Remove the outside portion of the template by gently pulling along the perforation. Affix the mask to the front of the speaker using a piece of tape. Fold the tape onto itself to form a double-sided loop. Affix the tape to the tweeter and place the mask onto the speaker.
The grilles should be painted before they are installed. For all models, the best
results will be obtained by using a spray gun or airless sprayer, thinning the paint (prevents clogging of the grille holes), and by applying several light coats instead of one heavy one.
Speaker Phase
Speaker wire has two conductors. One conductor is attached to the negative (-) terminals and one conductor is attached to the positive (+) terminals of both your speaker and your amplifier. Usually, the wire is marked for your convenience. There are different ways wires are marked: a stripe on one wire, a ribbed area of one conductor you can only feel, different col- ors of metal wire on each conductor, or there might be a fabric strand or string wound into one of the conductors. Of course, there are some wires which appear completely identical. Be careful, or you might make a mistake.
If you make a mistake, one speaker will be playing “out-of-phase” with the other speaker. An out-of-phase pair of speakers work against each other and the sound of the two speakers playing together will be lacking in bass and be “phasey” sounding. If you suspect the sound is not right and you cannot see any markings on the wire, try this simple test:
1.Stand half way between the speakers.
2.Play some music with the amplifier or radio set to Mono.
3.Listen to the richness of the bass and the loudness of the sound.
4.Turn off the amplifier and reverse the connections on one amplifier chan- nel only.
5.Repeat the listening test with the same setting of the volume control. When the sound has a richer bass and is slightly louder the speakers are working together or “in-phase”.
Final Installation in New or Existing Construction
